In a perfect world, every prop and gimmick we use would be examinable, but sadly in the absence of genuine magic we need methods. We also need to keep these methods a secret, and so a significant proportion of the items we use, cannot be scrutinised by our audience members.
It is our job to stop the desire for the prop to inspected. Therefore, the gimmick should be by design unsuspicious and handled in an unsuspicious way. Everything should appear innocent.
Audiences vary, some people are more curious than others, friends and family don’t have the social boundaries as polite strangers. We need to be aware of who we are performing for and have strategies for potential issues.
A hobbyist is more concerned about examinability than a professional because of the nature of the performance, environment, and their audience. A professional can pocket everything and be on their merry way.
I don’t think there is a 100% solution to this issue, assuming you can’t switch the prop in the question at some opportune moment. The best one can do, is to be as fair as the gimmick allows.
I’m not one for encouraging inspection of my props anyway, it is just dead time and can turn the magic into a puzzle. I don’t want to be asking them to find a solution. If an item is of curiosity, I spin a tale of how it came into my possession and give it a colourful history. I’ve found this does tend to stop people thinking of it as a ‘magic item’.
I also draw attention to innocent details of the prop which the participant can look at; this may even allow the object to be handled freely by the participant as the focus is on a feature rather than item as a whole. Plus, they don’t know what is going to happen in the trick yet so have no clue if they should be looking for something or not. Fingers crossed at the end of the routine; they will remember they checked the prop out.
In my experience an organic looking prop is usually taken for what it appears to be, a regular bottle, die or box with a padlock. I can’t explain why, but I suppose the lay-person hasn’t be exposed to the lengths of gimmickery we have, and would find the idea of paying £100 for a keyfob implausible. This is only the case if the prop doesn’t actually appear to do something itself such as change colour or produce increasing amounts of water etc.
The one item we all use that is often suspected is playing cards. Fortunately, most gimmicked decks can be shown fairly, even the Invisible Deck has an innocence about it. I use Phil Plus Outdone all the time and no one has asked to see the cards, two cards have been handled by them and the deck has been clearly displayed.
Again, if the nature of the card trick is a colour changing deck, you will need to prepared to end clean as the trick itself draws attention to the cards.
Fear of examinability is never going to go away, but I do think it is given too much weight at inappropriate times. Rarely does anything get examined thoroughly before a trick begins, a participant is not going to get a magnifying glass out while the rest of the audience whistle to themselves.
Display things innocently at the beginning and give attention to the magic moments, not the objects being used.